Renal Vascular Disease

What is renal vascular disease?

Renal vascular disease is the name given to a variety of complications that affect the arteries and veins of the kidneys. These complications affect the blood circulation of the kidneys, and may cause damage to the tissues of the kidneys, kidney failure, and/or high blood pressure.

Vascular conditions affecting the renal arteries and veins include the following:

renal artery stenosis
Renal artery stenosis is a blockage of an artery to the kidneys. It may cause kidney failure and hypertension (high blood pressure).

renal artery thrombosis
Renal artery thrombosis is the formation of a clot in a renal artery. A thrombosis of a renal artery may cause kidney failure because of blocked blood flow to the kidney.

renal artery aneurysm
A renal artery aneurysm is a bulging, weakened area in the wall of an artery to the kidney. Most of these aneurysms are small (less than two centimeters, or about three-quarters of an inch) and without symptoms. Renal artery aneurysms are uncommon and are generally discovered during diagnostic procedures performed in relation to other conditions.

atheroembolic renal disease
Atheroembolic renal disease occurs when a piece of plaque from the aorta and/or other large arteries breaks off and travels through the bloodstream, blocking small arteries such as the renal arteries. Atheroembolic renal disease is becoming a common cause of renal insufficiency (poor kidney function) in the elderly.

renal vein thrombosis
A renal vein thrombosis is the formation of a clot in a vein to the kidney.

Renal vascular disease is often associated with hypertension (high blood pressure). Hormones which influence blood pressure are affected by kidney function. Decreased blood flow to the kidney(s) as a result of renal vascular disease may cause an excessive amount of renin to be produced. Renin is a powerful hormone that increases blood pressure.

What causes renal vascular disease?

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The cause of renal vascular disease will depend on the specific condition involved:

renal artery stenosis
Stenosis (blockage) of a renal artery may be caused by atherosclerosis (a build-up of plaque, which is a deposit of fatty substances, cholesterol, cellular waste products, calcium, and fibrin in the inner lining of an artery) or other conditions, such as fibromuscular dysplasia (a condition that weakens the walls of medium-sized arteries and occurs predominantly in young women of childbearing age), and Takayasu's arteritis (a rare inflammatory disease affecting the aorta and its branches, including the renal arteries). Atherosclerosis is the major cause of renal artery stenosis.

renal artery thrombosis
Formation of a thrombosis (clot) inside one of the renal arteries may occur as a result of trauma, infection, inflammatory disease, renal artery aneurysm, or fibromuscular dysplasia.

renal artery aneurysm
There are four types of renal artery aneurysms:

saccular - bulges or balloons out only on one side of the artery

fusiform - bulges or balloons out on all sides of the artery

dissecting - weakened artery wall due to a tear in the inner layer of the artery wall

intrarenal - occurs on an artery inside the kidney

Saccular aneurysms may occur as a result of a congenital (present at birth) weakness of an artery wall or trauma. Atherosclerosis may also be a factor. Fusiform aneurysms most often occur with fibromuscular dysplasia. Intrarenal aneurysms may be congenital, or may result from trauma.

atheroembolic renal disease
Small pieces of plaque (emboli) from atherosclerosis formation in other arteries of the body may break off and travel to the renal arteries, blocking blood flow to the kidney. Emboli may occur because of surgery, insertion of a catheter, or the use of blood-thinning medications. The disease most commonly affects older persons.

renal vein thrombosis
Conditions associated with the presence of renal vein thrombosis include trauma, compression of a renal vein by an adjacent structure such as a tumor or aneurysm, nephrotic syndrome (results from damage to the kidneys' glomeruli, the tiny blood vessels that filter waste and excess water from the blood and send them to the bladder as urine), pregnancy, administration of steroid medications, and use of oral contraceptives (birth control pills).

Risk factors for renal vascular disease include:

age

female gender

atherosclerosis

hypertension, particularly new onset of hypertension in an older person

smoking

high cholesterol

diabetes

A risk factor is anything that may increase a person's chance of developing a disease. It may be an activity, such as smoking, diet, family history, or many other things. Different diseases have different risk factors.

Although these risk factors increase a person's risk, they do not necessarily cause the disease. Some people with one or more risk factors never develop the disease, while others develop disease and have no known risk factors. Knowing your risk factors to any disease can help to guide you into the appropriate actions, including changing behaviors and being clinically monitored for the disease.

What are the symptoms of renal vascular disease?

Symptoms of renal vascular disease vary depending on the type of disease and degree of involvement present. Symptoms of various types of renal vascular disease include, but are not limited to, the following:

sudden onset of flank (between the ribs and the upper border of the hip bone) pain and tenderness

fever

blood in the urine

nausea and/or vomiting

sudden decrease in kidney function

hypertension

more gradual or incomplete blockages:

may be asymptomatic (without symptoms) and go undetected

renal artery aneurysm

generally asymptomatic

hypertension may be present in up to 90 percent of persons with a renal artery aneurysm

dissecting aneurysms (caused by a tear in the inner layer of the artery wall) may cause flank pain and blood in the urine

atheroembolic renal disease

skin lesions such as purpura (a type of rash in which blood cells leak into the skin or mucous membranes)

mottling (discolored areas) of the toes and feet

kidney failure (either sudden or occurring over a longer period of time)

abdominal pain

diarrhea

confusion

weight loss

fever

muscle aches

renal vein thrombosis

chronic (over a period of time) onset:

most often asymptomatic

acute (sudden) onset:

persistent severe flank pain that may be spasmodic (with spasms) at times

soreness in the area over the kidney, between the ribs and the backbone

decreased kidney function

The symptoms of renal vascular disease may resemble other medical conditions or problems. Always consult your physician for a diagnosis.

How is renal vascular disease diagnosed?

In addition to a complete medical history and physical examination, diagnostic procedures for renal vascular disease may include any, or a combination of, the following:

arteriogram (Also called an angiogram.) - an x-ray image of the blood vessels used to evaluate various conditions, such as aneurysm, stenosis (narrowing of the blood vessel), or blockages. A dye (contrast) will be injected through a thin flexible tube placed in an artery. This dye makes the blood vessels visible on x-ray.

duplex ultrasound - a type of vascular ultrasound procedure performed to assess blood flow and the structure of the leg veins. The term "duplex" refers to the fact that two modes of ultrasound are used - Doppler and B-mode. The B-mode transducer (like a microphone) obtains an image of the carotid artery being studied. The Doppler probe within the transducer evaluates the velocity and direction of blood flow in the vessel.

renography - a specialized radiology procedure used to assess the function and structure of the kidneys. Renography is a type of nuclear radiology procedure. This means that a tiny amount of a radioactive substance is used during the procedure to assist in the examination of the kidneys.

Treatment will also vary depending on the type of renal vascular disease that is present.

Type of renal vascular disease

Treatment

renal artery stenosis

medical treatment:

angiotensin-converting enzyme (ACE) inhibitor medication may be prescribed to treat hypertension in patients with fibromuscular dysplasia

antihypertensive medications may be used to treat high blood pressure

in stenosis caused by atherosclerosis, medications to lower cholesterol may be prescribed

treatment of related medical conditions such as diabetes

surgical treatment:

endovascular procedures such as angioplasty (the opening of a renal artery using a balloon or other method) or placement of a stent (a tiny expandable metal coil placed inside an artery to keep the artery open)

open surgical procedures to bypass the occluded renal artery. There are several variations of such procedures.

renal artery thrombosis

Treatment of a renal artery thrombosis depends on the type (acute or chronic) of thrombosis, and the length of time since the thrombosis occurred.

In acute situations, thrombolytic ("clot-busting") medication may be infused into the renal artery for several hours to several days to break up the clot.

Surgery to remove the clot or bypass the artery may be performed in some situations.

renal artery aneurysm

Treatment of a renal artery aneurysm depends on factors such as size and location of the aneurysm and whether or not symptoms are present. Certain types of small (less than two centimeters, or about three-quarters of an inch) aneurysms may not be treated, but may be observed for growth or development of other complications.

Larger aneurysms (greater than two centimeters or three-quarters of an inch), dissecting aneurysms, aneurysms causing kidney ischemia (lack of blood flow to the kidney tissue) and hypertension, aneurysms that are growing larger, and aneurysms causing symptoms may be treated surgically.

Because of the increased risk for rupture (bursting), a renal artery aneurysm in a pregnant woman or a woman of child-bearing age will generally be treated surgically.

atheroembolic renal disease

Treatment of atheroembolic renal disease depends on the extent of the disease and the individual situation.

Medical treatment may include medications to reduce cholesterol, blood pressure, and other related medical conditions, such as diabetes.

Surgical treatment may include:

endovascular procedures such as angioplasty (the opening of a renal artery using a balloon or other method) or placement of a stent (a tiny expandable metal coil placed inside an artery to keep the artery open)

open surgical procedures to bypass the occluded renal artery. There are several variations of such procedures.

renal vein thrombosis

Renal vein thrombosis is generally treated medically with anticoagulant (keeps the blood from clotting) medication. Anticoagulants may be given intravenously (IV) for several days, then given orally for several weeks up to an indefinite period of time.